The present invention relates to mixing apparatus comprising a conical container having an upper cover and a vertical axis. The mixing screw is supported at the upper end of the container from a central drive shaft to which the inner end of a radial arm is connected, the outer end of which is connected to the upper end of the mixing screw, so as to extend parallel to the conical container wall and to be driven so as to simultaneously rotate around its axis and revolve around the axis of the container.
Mixing apparata are known and may also be used as vacuum drying apparatus. If applied in the pharmaceutical industry, where the mixed material must remain clean and particularly sterile, the mixing apparatus has the disadvantage, that the seals and seams allow material and bacteria to enter and be retained. Furthermore, in the same areas, cleaning liquid, used for cleaning the container, e.g. when shifting to a different material to be mixed, can also be retained. In each instance, the sterility and cleanliness of the apparatus is jeopardized. The invention aims at removing such disadvantages.